How are underground mining and surface mining used to extract chromite deposits?

Chromite deposits are extracted using both underground and surface mining techniques. The choice between these methods depends on the depth, size, shape, and orientation of the ore body, as well as the grade of the mineralization.12

Surface Mining

Surface mining is typically employed when ore deposits are located near the surface. This method is often more productive than underground mining because it allows for the use of larger equipment and provides easier access to the ore. However, it frequently requires the removal of significant amounts of waste rock to uncover the deposit.2

Underground Mining

When an ore body lies at a considerable depth, the cost of removing the overlying waste to reach it via surface mining becomes prohibitive, necessitating underground techniques. Underground mining is generally more expensive and less productive per worker than surface mining due to limited access and the need for smaller equipment. The process involves creating openings known as stopes through a two-step sequence: development, which prepares the ore blocks, and production, or stoping, which extracts the ore. The specific underground method selected is heavily influenced by the rock's structural integrity and the dip of the deposit.2